Substation apparatus



V. A. HAIN.

SUBSTATION APPARATUS.

APPLICAHON HLED IUNE 23. 1916.

I'utcntcdfiept. 9, 1919. Fig. I.

Inventor:

Veit 0 1. Hair-1, sMZJM- His fitter-neg UNITED STATES PATENT OFFICE,

ELECTRIC COMPANY, A

' sunscmrron n'rrmros.

Specification of Letters Patent.

Patented fiept. 9, 1919.

Application and June as, me. Serial 110. 105,506.

To a ll whom it may concern: I Be it known that I, Varr A. HAIR, 0. mt:-

zen of the United States, residing at Qhiicage, in the county of Cook, State of Illino have invented certain new and useful Improvements in Substation Apparatus, of which the followin is a speci cation.

My invention re ates to sub-station ap- 'paratus, and more particularly to an ar- 10 rangement for the protection -of rotary transformers which are interposed between two systems, whereby, at the same time, the greatest possible continuity of service will be maintained. a

Rotary transformers as used in sub-stations are subject to severe overloads, especially when used in railroad service. Adequate protection canbe secured by the use of overload circuit breakers but if these must be manually reset, the service is interrupted for a greater or less period. The problem then is to provide some arrangement which shall protect the apparatus, and at'the same time maintain t e continuity of service to as high a degree as possible. The arrangement which I shall herein propose is adapted for use with any rotary transformer connecting two systems, but it is especially adapted, because of its automaticoperation. to use in remote control sub-stat ons or in sub-stations which are entirely automatic.

My invention consists in an arrangement for protecting a rotary transformer upon the occurrence of overloads which shall at the same time put said transformer in service again within as short a s ace of time as possible, and which shall come in, effective after having operated for a predetermined number of times at predetermined intervals.

M invention will be more readily understood from the following specification taken in connection with the accompanying drawing, in which Figure 1 is a diagram showing my invention applied to a remote-control sub-station; Fig. 2 is a diagrammatic view showing the one of the relays used.

Although I have herein illustrated my invention as applied to a remote-control sub-station in which the rotary transformer is started by an operation at the main generating station, it will be understood that it is equally applicable to a sub-station which detailed construction of is entirely automatic or to a? manually-controlled sub-station.

In the arran ement shown the-apparatus which is located at the main generating station, is inclosed within a dotted square at the lower. lefthand corner of the sheet. An alternating current generator 10, supplies current to a supply-s stem 11. This supply system is adapted to cconnected to feeders 12 through a switch 13, a starting transformer 14, and a voltage regulator 15 preferably of the induction type. The remaining apparatus by means ofwhich power is supplied to the direct current distribution system 16, is located a a sub-station which may be at any desired distance from the generating station.

The sub-station will be seen to include a rotary transformer 20, here shown as a notary converter, which is, adapted to be connected to the low. voltage and full voltage taps respectively,'of the Starting compensator 23. The latter is supplied with alternating current from the feeders 12 through the line switch 24. It will be seen that the switches 21 and 22 are mechanically connected by means of a pivoted bar 25 so that they are interlocked and further so that the switches will remain in the position to which they are moved by the energization of one s01 the other of theirv coils. This is, however, only intended as a diagrammatic representation of any construction adapted to operate in the desired manner. The direct current terminals of the rotary transformer are adapted to be connected to the distributlon system 16 by means of a circuit breaker 30. This circuit breaker may be of any suitable type, and will be seen to comprise a closing coil 31, a trip coil 32, and an interlock switch 33. The energization of the closing coil is controlled by the contacts of a differential voltmeter 35, having one coil responsive to'the vvoltage of thedist-ributioh system, as determined by other sub-station's or generating stations, not shown, and the other coil responsive to the terminal voltage of the rotary transformer. lVh'en the voltage of the rotary transformerjs slightly greater than that of the distribution sys-' tem, the contacts of this voltmeter will be closed and cause the energization of coil 31,

provided the circuit breakeris in its 0 en position so that the switch 33 will cbmp etc the energizing circuit.

and then become inefl'cctirc.

.trolled b a centriugal speed res onsive switch 53'. 'When the rotary trans ormer has attained relay An overload relay 40 has been provided which is responsive to the power transferred between the supply system and the distribution system, and has the two switch members 41 and 42. Switch 42 is arranged to complete an energizing circuit for the trippin r in its 0 used mention. The trip ing coil is also'arranged to be energized rom either a. centrifugal speed limiting switch 53 or from a reverse current relay 36. The energizing circuit for the instantaneous relays 43 and 4-1 is completed tlirou h the switch 41 on the overload relay. T e first of .theserelaysis in normally closed position when deiinergized, and energizes the time limit relays 45 and 46 of s ccial construction, as shown in Fig. 2. elay 44 is adapted to energize ,the starting contactor 21 while the time limit relay 45 is adapted to energize the running contactor 22.

The construction of the time limit relays 45 and 46, one conception of which 15 diagrammatically shown in Fig. 2, is such that they may be closed for a )redetcrmmcd number of times at predetermined intervals, To this end, each of these relays may have one of its contacts mounted upon a movable member 61 which is mechanically connected to the core 62 of the closing solenoid. Mounted upon the movable member 61 is a spring pressed pawl 63, engaging a ratchet 6-! provided with a she pin 65. At each closure of the contacts, t e pawl 63 will more the ratchet wheel 64 forward for one notch until it has been actuated for a number of times determined by the desi of the ratchet wheel 6-1 and the location 0 the stop pin 65. After this number of closing movements has taken place, the stop pin 65 will engage some fixed member, such as the support 66, to prevent further closure of the switch. The time interval between the energization of the coil and' the closure of the switch is determined b any suitable device, such as the dashpot til, b means of which the closing movement may be retarded for any suitable interval oi time.

,The .rotarytransfonner is provided with an exciting winding; 50 whose circuit is conmeans 0 a. field contactor 51 and the desired speed, which will preferably be slightly less than synchronous speed, the switch 53' will energize the field contactor 51 and connect the exciting winding 50 between the positive and negative sides of the distribution circuit 16 through the winding of the protective relay 58, the resistances 54 and 55, and the winding of the protective 59. As is customary in railway worlr, the negative side of the distribution circuit is grounded, as has been indicated coil 32 when the circuit breaker in Fig. 1. The winding of the contactor 51 is protected from overheating by means of a resistance 52 which is shbrt circuitcd in the open position of the contactor. In 111- allcl with this winding is the winding 0 the time limit relay 56, whose contacts control the encrgization oiwa contactor- 57 whose contacts are arrangcd iiiscries with those of the Fold) 46 to short circuit thcrcsistancc 55.

Assuming that the distribution circuit 16 is energized from some other solace of supply, land that the generator 10 is supplying current to the supply system 11. the rotary transformer-may he set in operation and connccted between the supfly system and the distribution system by he operator at the main generating station. It will be a sumed that the line switch 24 is in its closcd position, and that the running cont-actor 22 is closed, bcin' energized through the contacts of the re av 15 which in turn-is energized through the relaylil. The operator will then move the voltage regulator'to its' maximum buck position and the switch 13 to its left hand )osition. The starting trans former l will supply a rcduccd voltage to the rotary 20, which will be still further rcdurcd by means of the voltage regulator 15. The rotary will then start and will gradually increase in speed until it reaches synchron-ism. iVhen the speed is slightly below synchronism, the speed responsive switch 5?, will energize the field contact'or 51 and runnect the exciting winding 50 to the distribution circuit with all of the irsistnnccs 5i and in circuit. This cxciting winding is prefcriilily connected to the distribution circuit instead of directly tothc terminals of the rotary transformer to insure that the voltage shall build up in the right direction. Thr operator will then mow the switch 13 to its right hand position so as to supply the full voltage of the system 11 to the fccdcrs 1:2. loss the reduction in tho. regulator 15. About this time the relay 56 which .has been retarded 'bv its time limiting dash-pot, will close and energize the contactor 57 so as to short circuit the resistance 55, thereby supplying full ficld current to the rotary transformer. The operator will then set the voltago regulatorlfi in its running position so that the A. C. voltage supplied to the rotary transformer will be slightly increased.

The particular method of starting the rotary transformer and putting the same in operation is, however, not an essential part of my invention. 'Sim'ilnrly the provision of a revcrsc current relay arranged to disconnm't the transformer from the distribution cirdistributi v the service assured with a minimum delay.

'=. If .the::cause of overload has in itsrlOscd position.

current voltage, and can .of power, as wellas the speed limiting switch 53, which is set to of. overload 112011] the.

found-that for this purpose,

load would 5 causecuit in'..case of a failure of' the alternating "sequentlya reversa closeata'higher speed than the switch 15331 and the field 'rotecting relays 58 and 59, areoldand'wellown.

Ivhave, however, provided an arrangement whereby, upon the occurrence of an overload, the transformer will beautomatically disconnected from "the distribution cirouit,.the supply voltage decreased, the exciaapmdetermined interval, and the transfonner- -then 'freconnected to the distribution-circuit; This action will be recatcd not more than a predetermined numr-of-times, say for example five tiines, so the short circuit or other cause distribution circuit shalL-ihave'cleared' itself in the meantim he,--transfonner may beconnected to the nlcircuit-and the continuity of that in :case

not been remy arrangement must to its originalcondioperation can be had cleared. It will be my invention is equally applicable to .a. manually controlled substation or to a remote controlled or an automatic sub-station. As has already beenpointed out, the occurrence of an overthe energization of the trip coil32 to'open the circuit breaker and at the same time will energizethe relays 43 and ,.44.;.-:The energization of the relay 43 will deener e'the relays 45.and 46 which .will-dmmediiftely open allowing the starting oohtaotorffil to be closed by means of the relay 44,-and the resistance 55 to be inserted in circuit with the exciting winding and thereby reduce the direct current voltage. .As soon as the circuit breaker has opened, the overload relay will open and again deiinerg'iz'e the relays 43-and 44. The starting contactor 21 will, however; remain After an interval, of say ten seconds, relay 45 will be again closed and will energize the running contactor 22 to increase the voltage supplied to the' rotary transformer. After an interval, of say h after the closing of the relay 45, the, relay 46 will be closed to short circuit the resistance 55. As soon as, the direct current voltage has reached a value slightly in excess of the voltage of the distribution circuit, the differential voltmeter35 will cause the eincuit breaker 30 to again close and if the cause of the trouble has not been removed, the overload relay 40 will again come into action and cause a repetition of the cycle whic has been described. This will be con ued at regular intervals and if the moved'at this time, be, normal! y (restored tion before further when 'the trouble -is '-.decreased,i=4 ;hesg conditions restored in the art. I do 11 seconds, or five seconds cause of the trouble has not been removed.

after a certain number of attempts to keep the transformer in service, then the construction of the relays 45 and, 46 is such that they will become ineffective and prevent further operation untilthey have been manually reset.

I have herein described one particular emhodiment of my invention whereby the objects set forth may be attained, but it will be understood that although I have shown my invention as applied to a particular type of substation. and as carried out with a particular arrangement of apparatus, it is equally applicable to any arrangement of a rotary transformer connecting a suppl system a'nda distribution system. It wil be further understood that various changes and modifications will occur to those skilled not wish, therefore, to be limited to the exact arrangement shown, but seek to cover. in the appended claims all those modifications which come within the true scope and spirit of my invention.

What I claim as new. and desire to secure by Letters Patent of the United States, is:

1. In combination, a supply system, adistribution system, a rotary transformer interposed between said systems, and means operable in response to electrical conditions of said transformer for effecting the connection and disconnection of said transformer systems and for first deincreasing the voltage apsaid means belerposed il 'etwcen said systems, means operable in response to the power transferred by said transformer for effecting the dis connection of said transformer and distribution system and for first decreasing and then increasing the voltage applied to said transformer by said supply system, said means being capable of automatic operation to increase said voltage only a predetermined number of consecutive times, and means responsive to the ratio of the voltages of said transformer and distribution system for reconnecting the same.

3. Incombination, a supply system, a distribution system, a rotarytransformcr interposed betwccn said systems, means operable in response to the power transferred by said transformer for effecting the disconnection of said transformer and distribution system and for first decreasing and after a predetermined interval increasing the voltage applied to said transformer by said supply system, said means being capable of automatic operation to increase said voltage only a predetermined number 02" consecutive transformer, said means being capable of automatic operation to increase said excitation only a predetermined number- 0f consecutive times.

5. In combination, a, supply s stem, a distribution system, a rotary trans ormer mterposed between said systems, means o rable in res JOIISB to the 'wer transferred y said trans ormer for e cting the disconnection of said transformer and distribution system and for first decreasingand then increasin the excitation of said transformer, sai means being capable of automatic operation to increase said excitation only a predetermined number of consecutive times, and means responsive to the ratio of the voltages of said transformer and distribution system for reconnecting the same.

0. In combination, a supply system, a distribution system, a rotary transformer interposed between said systems, means 0 erable in res mnse to the power transferred y said trans ormer for effecting the disconnection of said transformer and distribution system and for first-decreasing and after a predetermined interval increasing the excitatio'n of said transformer, said means being capfi ble of autonm'tic operation to increase said" excitation only apredetermmed number of consecutive times, and means responsive to the ratio of the voltages of said transformer and distribution system for reconnecting the same.

7. In combination, a supply system, a distribution system, a rotary transformer interposed between said systems, and means operable in response to electrical conditions of said transformer for cil'oeting the connection and. disronnertion of said transformer and one of said systems and first destem, a discreasing the voltage applied to and the excitation of said transf rmer and then increasing the volta e app ed to and the excitation of said trans ormer,"said means being capable of automatic operation to increase the volta e applied to and the excitation of said trans ormer only a predetermined number of consecutive times.

8. In combination, a supply system, a distribution system, a rotary trans ormer interposedbetween said systems, means'o rable 1n res ones to the ower transferred y said trans ormer for e ecting thedisconnection I of saidtransformer and distribution system and for first decreasing the voltage applied, by said supply system to and the excitation of said transformer and after a predetermined interval increasing the voltage applied by said supply'system to and the excitation of said transformer, said means being capable. of automatic operation to increase the voltage applied to and the excitation of said transformer only a predetermined number of consecutive times, and neans responsive to the ratio of the voltages of said transformer and distribution system for re connecting the same.

9. In combination, a supply system, a distribution system, a rotary transformer interposed between said systems, means operable in response to the power transferred by said transformer for effecting the disconnection of said transformer and distribution system and for first decreasing the voltage applied by said suppl system to and the excitation of said trans ormer and after a predetermined interval increasing the voltage applied by said supply system to said trans I former and subsequently increasing the excitation of said transformer, said means being capable of automatic operation to increase the voltage applied to 'and the excita tion of said transformer only a predetermined number of consecutive times, and means responsive to the ratio of the voltages of said transformer and the distribution system for reconnecting the same.

In witness whereof. I have hereunto set my hand this 17th day of June, 1916.

vsrr A. HAIN. 

